☠ Purge and Replenish
This does not necessarily have to be a rapid or expensive process, just one done with thought and consideration.
☠ Take Selfies
If you are going to post an outfit image for review, I think it is important to get a clear whole-body photograph, with lighting that gives clear visibility of details, drape, etc. (difficult with black clothes!) and to also include detail shots if there are specific details you feel contribute to the outfit but are not necessarily visible on a whole-body photograph.
Remember that constructive criticism is a mixture of tips that genuinely work and personal opinion; for example, a lot of Lolitas think that fingerless lace gloves are not suited to Lolita, but I think that as long as the lace is good quality, that they do as I cannot see a good reason for them to not fit in the Lolita aesthetic. If you really love something, wear it, but also do listen to those who give reasons with their constructive criticism.
☠ Test Outfits Before Wearing
If you have a dress-maker's dummy this is probably the best way of doing this, but if not, there's plenty of ways of constructing make-shift mannequins to fulfil this. One thing I do is take two coat-hangers, one being my 'shoulders' and the other suspended below to be my 'hips' and hang my clothes from the pair as if I were dressing them; that way I get an idea of what the clothes look like together before I actually put them on. I tend to only do this with outfits for special occasions, especially as I can get four (or more) coat-hangers, and put together two outfits next to each other for comparison. This does not replace testing an outfit on at home before an occasion, but it does help the process.
Another option is to do a 'flat lay' - this is laying out an outfit on a bed or (clean!) floor to get a two-dimensional representation of how an outfit might work. Layer clothes carefully so you get some idea of how layering when worn will look like, and remember that details can be lost in layering, so if you have a nice print, embroidery or other detail in an item that you wish to showcase, do check to see if they're still visible once worn.
Whichever option you choose, this is a good way if assessing how items combine. You can also note down which items go well together, but just do not suit a specific outfit (or 'co-ord' short for 'co-ordinated' in Lolita parlance) and which items just don't seem to fit any outfit (even if they're nice on their own) and mark them as something to either replace, or build an outfit around that does work (depending on whether you are trying to expand or reduce your wardrobe).
I hope people find these tips useful in developing their own personal style and and in improving their outfits. Developing your own style is based around what you personally like (rather than what is trendy, or what is popular with others) and on what sort of things look aesthetically pleasing together (including deliberately clashing, if that is your thing) and learning over time what suits you, in your own estimation.
Don't rely too much on others; it is useful initially (especially in a fashion like Lolita that is built around a framework of 'rules' or 'guidelines' that are based in what is tried and tested to work to create a certain aesthetic) but in the end, for something to be your own personal style, you need to develop it yourself. You can learn from others and imitate to a certain degree (but outright copying people's style is considered a bit weird and rude) but remember, that your style is something that should come out of your aesthetics, not someone else's.
Be patient, especially if you are a teen; you probably won't settle into something that is your groove, your style, your own way of doing things until you're in your late 20s or even early 30s, and it is perfectly fine to experiment. I went through several different subcultural styles and variations on Goth before I settled on Romantic Goth, and even now, my style is evolving (just more slowly) as I evolve. We all change over time, and it is important not to stagnate.